Let's do a quick comparison with gathering professions, see how disenchanting compares.
Let's go farming. If we were miners we'd find nodes, herbalists we'd find herbs. I can't seem to find the shard deposits.
Maybe it's like skinning. They both kill mobs, loot them, do some hand-waving and then they have mats. But skinning doesn't actually need to kill anything, it can follow others and skin their kills. Enchanters could trade with them for greens and not kill either, but there's a significant difference here: the skinner does not take anything from the other player, the enchanter does. The skinnable corpse has no value except to skinners while unwanted items have vendor value for anyone.
It doesn't look like disenchanting is like any of the gathering professions. Maybe it's a crafting profession. Let's see how it compares.
Let's start with raw materials of some sort: herbs, cloth, greens. A scribe will crush the herbs into pigments which have no value except to scribes, a process which is similar to disenchanting. He can then turn these into a valuable product such as glyphs. If you trace the vendor value, you'll see that he actually loses gold to NPCs when he turns a 50s parchment into a 1s glyph just as enchanters turn 5-25g greens-epics into mats with no vendor value at all; but both glyphs and enchants are highly valuable to players.
In other words: crafting professions take something with low value to players or NPC and turn it into something of high value to players.
There is still the strange issue of enchanting having no gathering profession which would suggest that enchanting is a dual profession. Perhaps that is unfair? If so, tailors would be in the same boat, having no corresponding cloth-gathering skill aside from their own boost to looting.
I know it can be hard to grasp, but disenchanting is not a gathering profession. It is instead a crafting profession. This means that two common gripes need to stop. First, non-enchanters need to stop complaining that enchanters would want compensation or at least control over their profession. Would you drop a bunch of mats in a BS' bags and demand a titansteel destroyer for no charge just because he happened to be in a heroic with you? Second, enchanters need to stop complaining about people rolling on 'their shards.' The unwanted loot is the group's and you consented to turn it into shards, those are the group's shards still.